Stabilization of methyl chloroform



United States Patent 3,364,270 STABILIZATION OF METHYL 'CHLOROFORMMilton 3. Blankenship, Midland, and Ralph McCarthy,

Bay City, Mich, assignors to The Dow Chemical Company, Midland, Mich, acorporation of Delaware No Drawing. Filed Oct. 27, 1965, Ser. No.505,419 4 Claims. (Cl. 260-6525) ABSTRACT OF THE DESCLGSURE Methylchloroform is stabilized in the presence of aluminum by incorporating inthe solvent an inhibiting amount of a cyanobenzaldehyde.

This invention relates to the stabilization of methyl chloroform. Moreparticularly, the present invention relates to the stabilization ofmethyl chloroform in the presence of aluminum.

It is known that methyl chloroform reacts violently with aluminum toform tars and gaseous reaction products.

It has now been found that this reaction may be substantially retardedor prevented by incorporating an inhibiting amount of acyano-benzaldehyde compound into the methyl chloroform. Ortha-, paraandmeta-cyanobenzaldehyde may each be used alone or in any combination.Only an amount of cyano benzaldehyde compound sufiicient to retard orstop the reaction of aluminum and methyl chloroform is required.Ordinarily, amounts of from about 0.5 to 1015 percent by weight (basedon the total weight of the composition) of cyano-benzaldehyde compoundmay be incorporated into the methyl chloroform. The preferredconcentration of cyano-benzaldehyde compound in the methyl chloroform isfrom about 1.0 to 5.0 percent by weight (based on the total weight ofthe composition).

The cyano-benzaldehyde inhibitor compounds of the invention may be usedalone or in combination with other non-reactive conventional inhibitors.Such cyanobenzaldehyde compounds are superior inhibitors when comparedwith related aldehydes, such as benzaldehyde.

The following examples are submitted for the purpose of illustrationonly and are not to be construed as limiting the scope of the inventionin any way.

Examples 1 and II 'Dilferent amounts of cyano-benzaldehyde compoundswere added to 10 milliliter samples of 1,1,l-trichloroethane.Concentrations were calculated as weight percents. An aluminum coupon[designated alloy 1100, 18 gage 0.20 percent Cu (maximum) 0.05 percentMn (maximum) 0.1

2. 3. 4. 5. 0 percent Zn (maximum) "ice (approximately 0.04 to 0.05 inchthick by 2 /2 inches by /2 inch)] was immersed in each test solution andscratched with a sharp tool beneath the surface of the test liquid. Thecoupon was observed visually and the results recorded in Table 1according to the following standards:

Key number: Indicated result We claim as our invention:

1. A composition inhibited against attack by aluminum which comprisesmethyl chloroform and an inhibiting amount of a cyano-benzaldehyde.

2. An inhibited composition according to claim 1 which contains 0.5 to15 percent by weight of ortho-cyano'benzaldehyde.

3. An inhibited composition according to claim 1 which contains 0.5 to15 percent by weight of para-cyano-benzaldehyde.

4. An inhibited composition according to claim 1 which contains 0.5 to15 percent by weight of meta-cyano-benzaldehyde.

References Cited UNITED STATES .PATENTS 2,997,507 8/1961 Monroe et al260652.5 3,128,315 4/1964 Hardies 260652.5

OTHER REFERENCES Every et al.: Materials Protection, vol. 3 (9), pp. 46and 47 (1964).

LEON ZITVER, Primary Examiner.

M. JACOB, Assistant Examiner.

